# IEA-ETSAP Optimization Modeling Documentation

A key strength of the IEA-ETSAP methodology is the detailed documentation. The detailed documentation is the result of a commitment to the highest levels of transparency by the IEA-ETSAP. The initial detailed documentation set in motion a positive cycle with the methodology being used for diverse applications. In turn the documentation of the diverse applications leads to knowledge sharing. Innovations now, regularly get shared and adopted by others. The decentralized model therefore is able to benefit from the fact that a large community is using it. The IEA-ETSAP methodology is the leading open source approach to energy scenarios modeling.

A step-by-step DemoS suite of models and a comprehensive platform with a complete TIMES-Starter model that can be readily transformed for a new application can be downloaded.

Limited support is available at This email address is being protected from spambots. You need JavaScript enabled to view it.. Non-ETSAP institutions who are interested in receiving more substantial support for the development of models based on the ETSAP model generators may request ETSAP Support for the payment of an annual fee.

- TIMES Documentation and Demo Models

- Part I: TIMES concepts and theory
- Part II: Comprehensive Reference Manual
- Part III: The Operation of the TIMES code (organization of the TIMES modelling environment)
- Part IV: VEDA 2.0
- Interpreting the dual solution of TIMES

Part I provides a general description of the TIMES paradigm, with emphasis on the model’s general structure and its economic significance. Part I also includes a simplified mathematical formulation of TIMES, a chapter comparing it to the MARKAL model, pointing to similarities and differences, and chapters describing new model options.

Part II constitutes a comprehensive reference manual intended for the technically minded modeler or programmer looking for an in-depth understanding of the complete model details, in particular the relationship between the input data and the model mathematics, or contemplating making changes to the model’s equations. Part II includes a full description of the sets, attributes, variables, and equations of the TIMES model.

Part III describes the organization of the TIMES modeling environment and the GAMS control statements required to run the TIMES model. GAMS is a modeling language that translates a TIMES database into the Linear Programming matrix, and then submits this LP to an optimizer and generates the result files. Part III describes how the routines comprising the TIMES source code guide the model through compilation, execution, solve, and reporting; the files produced by the run process and their use; and the various switches that control the execution of the TIMES code according to the model instance, formulation options, and run options selected by the user. It also includes a section on identifying and resolving errors that may occur during the run process.

Part IV provides a step-by-step introduction to building a TIMES model in the VEDA2.0 user interface for model management and results analysis. It first offers an orientation to the basic features of VEDA2.0, including software layout, data files and tables, and model management features, both for handling the input and examining the results. It then describes in detail twelve Demo models (available below) that progressively introduce VEDA-TIMES principles and modeling techniques.

**VEDA-TIMES Demo Models**

This is a set of VEDA-TIMES models that start from an energy balance of EU27 and focuses on building a model incrementally employing a standard approach to describing the underlying Reference Energy System (RES) and careful naming conventions. The model starts with a simple supply curve feeding a single demand and grows step by step to build out the RES adding new commodities, technologies and regions; introducing new parameters and more advanced TIMES modelling features along the way. There are twelve steps with some variants in this set of basic and intermediate demo models.

**VEDA-TIMES Advanced Demo Model**

The advanced VEDA-TIMES DemoS steps are based on the structure developed for the basic VEDA-TIMES DemoS (from DemoS_001 to DemoS_012), using a series of six steps implemented through additional scenarios and subres workbooks, to progressively include some additional VEDA-TIMES features. The complete VEDA-TIMES Advanced Demo is assembled in the single VEDA_Models subfolder called DemoS_Adv. In this folder are all the sub-folders and Excel workbooks needed by VEDA for setting up and using the model.

New VEDA-TIMES users should start first with the VEDA-TIMES basic DemoS and then move to this version of the model.

- TIMES Extensions:

- Price elastic supply curves in TIMES
- Macro
- Macro MSA
- TIMES Stochastics
- TIMES Objective Variants
- Electricity Grid modeling
- Residual Load Curves in TIMES
- Dispatching and Unit Commitment in TIMES
- Enhancing the flexibility in TIMES: Introducing Ancillary Services Markets
- Retrofits and Lifetime Extensions in TIMES
- TIMES Micro - Elastic Demand Functions

- Getting Started

- ANSWER-TIMES Getting Started Manual (version 1.1)
- ANSWER-TIMES Starter Model Guidelines (more details on the starter model are available here)

- MARKAL

MARKAL is the predecessor of TIMES. MARKAL code will continue to be supported in its current form but no updates will be done.

- Part I: Standard MARKAL
- Part II: MARKAL MACRO
- Part III: SAGE
- Appendix A: MARKAL Matrix

- Annexes Final Reports

- Energy Systems And Sustainable Goals

Annual Report of Annex XV (2020-2022) - Understanding and facilitating the energy transition to achieve the 'well below 2oC' goal

Final Report of Annex XIV (2017-2019) - Tools for Analysis of a Future Energy Revolution (TAFER): Methodologies, Tools and Data Bases

Final Report of Annex XIII (2014-2016) - Policy Analysis Tools for Global Sustainability: E4 systems tools and joint studies

Final Report of Annex XII (2011-2013) - Joint Studies for New and Mitigated Energy Systems

Final Report of Annex XI (2008-2010) - Global Energy Systems and Common Analyses

Final Report of Annex X (2005-2008) - Exploring Energy Technology Perspectives. Energy Models Users’ Group

Final Report of Annex IX (2002-2005)